1. Field of the Invention
The present invention relates to a disk brake device suitable for a motorcycle.
2. Description of Background Art
A motorcycle provided with a caliper having three cylinders in parallel is known (for example, refer to JP Patent No. 3881756 (FIGS. 3-5).
A disk brake device is shown in FIG. 3 of Patent Document 1. In the description hereafter, reference numerals in brackets are the same as those shown in JP Patent No. 3881756 (FIGS. 3-5).
Cylinders (13), (14), (15) housing three pistons (20), (21), (22) are provided on a caliper body (12). The cylinder (13) and the cylinder (15) are connected by a first hydraulic passage (a1). The cylinder (15) is connected with an external section by a second hydraulic passage (a2). The cylinder (14) is connected with an external section by a third hydraulic passage (b). In other words, a brake hose is connected to the second hydraulic passage (a2) and the third hydraulic passage (b).
As shown in FIG. 4, the third hydraulic passage (b) inclines. Although the reference numeral is omitted, a projection can be seen forming the second hydraulic passage (a2) in the back of the third hydraulic passage (b).
As shown in FIG. 5, the second hydraulic passage (a2) is provided closer to the disk plate (18) than the third hydraulic passage (b).
The cylinder (14) must be connected to the air discharge (reference numeral omitted) so that the center cylinder (14) is smoothly filled with brake fluid. As shown in FIG. 3, the air discharge, third hydraulic passage (b) and second hydraulic passage (a2) are provided in relative proximity on the caliper body (12). When the air discharge is opened or closed using a wrench, an operation must be performed on the third hydraulic passage (b) and second hydraulic passage (a2) by threadably connecting one end of the brake hose with a tool. The operation is obstructed when the wrench or tool interferes with nearby brake hoses.
In the past, the air discharge, third hydraulic passage (b) and second hydraulic passage (a2) were relatively inclined. Thus interference of the wrench or the tool could be avoided by relatively inclining these components.
However when the air discharge, third hydraulic passage (b) and second hydraulic passage (a2) were relatively inclined, the caliper body (12) must be inclined with respect to a drill and a complicated operation is required to open holes with respect to the air discharge, third hydraulic passage (b) and second hydraulic passage (a2) in order to adjust the angle of inclination. Consequently the number of operations is increased.
As a result, there is a need for a caliper structure to reduce the hole opening operations.